A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.
The compressor section and the turbine section of conventional gas turbine engines are coupled by one or more shafts or spools. More specifically, a low pressure compressor and a low pressure turbine may be coupled by a low pressure spool and a high pressure compressor and high pressure turbine may be couple by a high pressure spool. Notably, however, the rotational speed of aft stages of a multistage compressor is often limited by tip speed constraints of the forward stages which have larger radii. Tip speeds of the aft stages could be increased by simply increasing their radius, but the blade height may become unacceptably small relative to the tip clearances which increase losses in a given stage.
Accordingly, a gas turbine engine with an improved compressor section would be useful. More specifically, a dual-speed split compressor having multiple stages rotating at different speeds for decreased compressor size and improved performance and efficiency would be particularly beneficial.